Tutorial on Type Classes and Relations in Coq (by Matthieu Sozeau and myself)

Hilbert's Epsilon operator and partial functions in Coq (V8.1)

The module ClassicalEpsilon of the new standard library (V8.1 beta)
allows us to use Hilbert's epsilon operator.
File Epsilon.v contains the definition of the
definite description operator iota, as well as some tactics for
dealing with descriptions and partial functions.
A small example is given, comparing partial
functions with some (total) implementations.